Cup bumper for Dolce Gusto pod brewer

I love this brewer, but it vibrates when making coffee. This causes any mug with a narrow base to slide across the support shelf. While it can't fall off (there's a lip) it does cause the dripping coffee to eventually miss the cup. I tried a variety of solutions, but this works the best.  Printed from TPU, it slides up from beneath and locks in place. It can be slid from left to right. It takes a little work to get it in place, but it holds well. Since it's flexible it provides tension and holds the cup in place.